/*
 * Copyright (C) 2021 Huawei Device Co., Ltd.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "message_handler.h"

namespace OHOS {
namespace MiscServices {
std::mutex MessageHandler::handlerMutex_;

MessageHandler::MessageHandler()
{
}

MessageHandler::~MessageHandler()
{
    std::unique_lock<std::mutex> lock(mMutex);
    while (!mQueue.empty()) {
        Message *msg = mQueue.front();
        mQueue.pop();
        delete msg;
        msg = nullptr;
    }
}

/*! Send a message
 * @param msg a message to be sent
 * @note the msg pointer should not be freed by the caller
 */
void MessageHandler::SendMessage(Message *msg)
{
    std::unique_lock<std::mutex> lock(mMutex);
    mQueue.push(msg);
    mCV.notify_one();
}

/*! Get a message
 * @return a pointer referred to an object of message
 * @note the returned pointer should be freed by the caller.
 */
Message *MessageHandler::GetMessage()
{
    std::unique_lock<std::mutex> lock(mMutex);
    mCV.wait(lock, [this] { return !this->mQueue.empty(); });
    Message *msg = reinterpret_cast<Message *>(mQueue.front());
    mQueue.pop();
    return msg;
}

/*! The single instance of MessageHandler in the service
 * @return the pointer referred to an object.
 */
MessageHandler *MessageHandler::Instance()
{
    static MessageHandler *handler = nullptr;
    if (handler == nullptr) {
        std::unique_lock<std::mutex> lock(handlerMutex_);
        if (handler == nullptr) {
            handler = new MessageHandler();
            return handler;
        }
    }
    return handler;
}
} // namespace MiscServices
} // namespace OHOS
